<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Hello React</title>
</head>
<body>

  <div id="root"></div>

  <script src="../lib/react.js"></script>
  <script src="../lib/react-dom.js"></script>
  <script src="../lib/babel.js"></script>
  
  <script type="text/babel">
    class App extends React.Component {
      constructor() {
        super()
        this.state = {
          message: "hello world"
        }
      }
      render() {
        return (
          <div>
            { /* 这里是注释 */ }
            <h2>{this.state.message}</h2>
          </div>
        )
      }
    }
    const root = ReactDOM.createRoot(document.querySelector("#root"))
    root.render(<App />)
  </script>
</body>
</html>